The present invention relates to a molded product and a process for manufacturing a molded product.
Typically, vehicle steering wheels are manufactured by resin molding. A core bar is first set in a metal mold at a predetermined position. Thereafter, a resin material is injected into the cavity of the metal mold and cured. A urethane resin is used as the resin material. A coating film having light resistance is formed on the surface of the resin molded part to prevent discoloration of the urethane resin by exposure to light.
A method of forming the coating film includes applying a coating to the inner wall of the metal mold (the surface of the cavity) prior to molding. More specifically, a coating solution is sprayed on the inner wall of the opened metal mold with a spray gun. The metal mold is closed and a filler material (urethane material) is injected into the mold cavity and cured. Thus, a molded product having a coating film on the surface is produced. A molding method in which a predetermined material is injected into the cavity and cured by a chemical reaction is called xe2x80x9creaction injection moldingxe2x80x9d (RIM).
However, when a coating solution is applied with a spray gun, the coating may be applied to parts other than the surface of the cavity or may scatter into the air without adhering to the surface of the cavity. Therefore, the adhesion efficiency of the coating is low. Since the coating applied to surfaces other than the surface of the cavity produces a burr after molding, the step of removing this burr is required. Further, the material that scatters into the air stains the work site.
On the other hand, when a coating solution is directly applied to a molded product with a spray gun, it is difficult to apply the coating uniformly. It is particularly difficult to properly apply the coating to the parting line of a molded product. Therefore, the light resistance of the steering wheel may not be complete.
It is an object of the present invention to provide a molded product having excellent light resistance and a manufacturing process for the same.
To achieve the above objective, the present invention provides a process for manufacturing a molded product having a coating layer on the surface. The process includes forming a coating layer on the wall surface of a cavity while a metal mold is closed, and filling a filler material in the cavity.
Another aspect of the present invention provides a molded product formed by injecting a filler material into the cavity of a metal mold, wherein the filler material is coated with a film having a substantially uniform thickness.
Further aspects of the present invention provide a steering wheel having a first side facing a driver and a second side, which is opposite to the first side. The steering wheel is coated with a film. The film is thicker on the first side than on the second side.
Further aspects of the present invention provide a process for molding a steering wheel providing a metal mold having a mold cavity. The cavity is formed such that a grip portion of the steering wheel faces downward. The process includes boiling a coating solution, during which a coating layer is formed on the wall surface of the cavity from the coating solution, and supplying a predetermined filler material into the cavity.
Further aspects of the present invention provide a process for manufacturing an insert molded product. The process includes setting an insert member in a metal mold, forming a coating layer on the wall surface of a cavity in the metal mold while the metal mold is closed, and depositing a filler material into the cavity.
Further aspects of the present invention provide an insert molded product formed by molding a filler material. The product includes an insert member, an intermediate layer formed from the same material as the coating film and located between the insert member and the filler material, and a coating film formed on the surface of the filler material, the coating film having substantially uniform thickness.
Further aspects of the present invention provide a method of coating a coating on the wall surface of a cavity in a metal mold. The method includes closing the metal mold, supplying a solution of the coating into the cavity, and depressurizing the cavity.
Further aspects of the present invention provide a method of coating a coating on the wall surface of a cavity in a metal mold. The method includes closing the metal mold, depressurizing the cavity, and supplying a coating solution into the cavity during the depressurizing step.
Further aspects of the present invention provide a molded product of a urethane resin formed by foam molding using water. The molded product includes a core portion molded by foaming a urethane material, and a coating film having a substantially uniform thickness, the film being formed on the surface of the core portion, wherein the surface characteristics of the metal mold is transferred to the coating.
Further aspects of the present invention provide a process for manufacturing a urethane resin molded product formed by foam molding using water. The process includes boiling a coating solution in a cavity in a metal mold while the metal mold is closed, during which time a coating film is formed on the wall surface of the cavity from the coating solution, and supplying a urethane material into the cavity at normal pressure.
Further aspects of the present invention provide a product molded with urethane material in a mold cavity. The product includes a core portion made of a highly foamed urethane material, a skin layer formed on the outside of the core portion, the skin layer being made of a urethane material that has less foaming than the core portion, and a coating film formed with a substantially uniform thickness on the surface of the skin layer, wherein the surface characteristics of the cavity are transferred to the film.
Further aspects of the present invention provide a process for manufacturing a foamed urethane molded product having a surface skin layer. The process includes depressurizing a cavity in a metal mold, boiling a coating solution in the cavity, forming a coating layer on the wall surface of the cavity during the boiling step, and injecting a urethane material into the cavity under reduced pressure.
Further aspects of the present invention provide a process for manufacturing a resin molded product, wherein molding and coating are performed simultaneously. The process includes applying a coating solution to the wall surface of a cavity in a metal mold, boiling the coating solution in the cavity under reduced pressure to form a coating layer on the wall surface of the cavity, heating a resin material to reduce flow resistance, supplying the heated resin material into the cavity, and curing the resin material in the cavity.
Further aspects of the present invention provide a product molded with resin material. The flow resistance of the resin material can be reduced by heating. The resin material is coated with a film having a substantially uniform thickness.
Further aspects of the present invention provide a process for manufacturing a urethane molded product. The process includes forming a coating layer on the surface of a cavity of a closed metal mold, first injecting a first urethane material containing a pigment into the cavity, and second injecting a second urethane material that includes a larger amount of pigment than the first urethane material.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.